What Are Uterine Fibroids? – Causes, Symptoms & Treatment

By BSc, MSc (embryologist) and BA, MA (fertility counselor).
Last Update: 04/15/2014

A uterine myoma, also known as uterine fibroid, fibromyoma or uterine leiomyoma is a beningn tumor in the female reproductive system. This tumor originates from the smooth uterine muscle layer, the myometrium. It is the most common beningn tumors in women; in Europe around 20% of women in their thirties or fourties, one out of five women in their reproductive age. The percentage rises to 40% in women aged over 50.

This tumor tends to appear in multiple nodules, although it can also grow as a single nodule. Its appearance and growth is directly related to hormones, mainly estrogens. When there is a hormonal imbalance and the levels of estrogens it can lead to the appearance of this kind of tumor, which is nothing more than the abnormal growth of muscular tissue.

A myoma can be from 0.31 inches up to more than 3.5 inches and they can weigh up to 2.2 pounds.

Types of uterine fibroids

Most of the times, these uterine fibroids are located in the uterine cavity and rarely in the cervix or the ovaries. According to its location we can differentiate among these type of tumors:

  • Intramural fibroids: they are located within the uterine cavity or myometrium. 40% of these fibroids are intramural.
  • Subserosal fibroids: they are the most common, around 50% of the cases. They grow in the outer part of the uterus.
  • Submucosal fibroids: they are located beneath the endometrium. Their frequency is 5%.

They can be found either in the outer or the inner part of the uterus, at the end of it as well as on the right part or on the left part of the uterus.


In the 30% of the cases, fibroids might be asymptomatic, but in other cases they might cause:

  • Pain in the pelvic area and abdominal bloating.
  • Painful periods
  • Metrorrhagia: bleeding between the expected menstrual period.
  • Menorrhagia: abnormally heavy and longer menstrual period.
  • Back ache, painful defecation, feeling pressure in the bladder...
  • Urinary frequency.


Diagnosing a uterine myome can be done through a pelvic examination followed by an abdominal or transvaginal ultrasound to confirm its presence. The diagnosis is more difficult with obese patient because the doctor cannot palpate the patient properly.

However, other tests can be run in order to check that there are no other ovarian tumors or that the Fallopian tubes are not bloated. These tests are:

  • Ultrasound: the image is distorted where the nodules are (hipoecogenic)
  • Radiography of the pelvis
  • Hysteroscopy: very useful to detect submucosal fibroids.
  • Magnetic resonance of the pelvis
  • Pelvic laparoscopy.

Note: if your doctor says that he thinks you might have a hypoechoic myoma, it means that, according to the results of your tests, s/he thinks that you might have a myoma.

Fibroids symptoms

Intramural fibroid treatment

Its treatment will depend very much on the patient's age, the size and weigh of the myoma and, also, on the wish to have children. The asymptomatic fibroids and the small fibroids do not need to be treated, but monitored.

Non-invasive treatments

  • Painkillers, such as ibuprofen to control the pain caused by small fibroids.
  • Contraceptive pills to regulate the periods and their pains.
  • Hormonal treatment reduces the level of estrogens in blood, creating thus a similar situation as that of menopause. For this reason, it is advisable to take into account the possible side effects. The treatment lightens the symptoms but does not make the fibroid disappear. Accordingly, once the treatment ends, the fibroids grow back again.

Invasive treatments (surgery)

  • Operative hysteroscopy, to remove the small fibroids within the uterine cavity by means of a small camera, which is introduced through the cervix.
  • Myomectomy (or fibroidectomy): it is the removal of the fibroids, but preserving the uterus. This removal does not ensure that the fibroids won't appear again in the future.
  • Laparotomy: just like the other two procedures, it implies removing the fibroids but, in this case, involving an incision through the abdominal wall.
  • Hysterectomy: it implies the complete or partial removal of the uterus; this surgery is performed on elder women who do not want to have children.
  • Uterine Artery Embolization (UAE): this procedure is used when dealing with small fibroids and it consists of blocking the blood supply to the uterine body, which makes the myoma to reduce in size or to disappear all at once. However, the possible side effects for women who long to become mothers are still unkown.

Surgically removing a fibroid

Risk factors

It remains unkown why these fibroids appear in healthy women, but estrogens have been proved to be related to the appearance of fibroids, because this hormone stimulates their growth. Therefore, women in their fertile age have a higher risk of enduring these tumors. Women heading to menopause have a lower risk because their level of estrogens in blood is also lower.

Other factors are: obesity, due to its relationships with estrogens; inherited and ethnic factors – it's been proved that Afro-Caribbean women have higher chances of suffering this type of tumour.

Fibroids and fertility

The presence of uterine fibroids has been regarded as a possible cause of infertility, although only 1 to 2.4% of infertile patients have uterine fibroids as the only cause of infertility.

One of the possible causes is that fibroids can press down on the Fallopian tubes, impeding thus, the fertilization of the egg.

These tumors have also been pointed out as a cause for recurrent pregnancy loss, due to the fact that the normal growth of the embryo can be affected by the size of the tumors.

For those women in their fertile age who want to get fertility back and get pregnant, the only way out is to undergo a myomectomy to remove the uterine fibroids.

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Authors and contributors

 Teresa Rubio Asensio
Teresa Rubio Asensio
BSc, MSc
Master's Degree in Medicine and Reproductive Genetics from the Miguel Hernández University of Elche (UHM). Teacher of different Clinical Embryology courses at the UHM. Member and writer of scientific contents at ASEBIR and ASPROIN. Embryologist specializing in Assisted Procreation at UR Virgen de la Vega. More information about Teresa Rubio Asensio
Adapted into english by:
 Sandra Fernández
Sandra Fernández
Fertility Counselor
Bachelor of Arts in Translation and Interpreting (English, Spanish, Catalan, German) from the University of Valencia (UV) and Heriot-Watt University, Riccarton Campus (Edinburgh, UK). Postgraduate Course in Legal Translation from the University of Valencia. Specialist in Medical Translation, with several years of experience in the field of Assisted Reproduction. More information about Sandra Fernández

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